The ad mirrored a message that Strickland — and most of his fellow Senate Democratic candidates — has voiced time and time again on the campaign trail, to the point where it can appear as if he isn't talking about anything else.

But it was actually the first time he has used that message in a TV ad. His first two spots, released earlier this month, highlighted his biography and his record as governor.

His outside group allies have been on the air far longer, but they too have avoided Trump. Senate Majority PAC, which supports Democratic candidates, has run ads about trade, China, and Social Security.

But Democratic strategists say the party has avoided focusing heavily on Trump in paid media for many reasons, including the belief that in a battleground Senate map chock full of blue states, the traditional playbook against Republican candidates (focusing on cultural issues and entitlement programs) is still effective.

They also caution that the party shouldn't lean too heavily into a message that, because of the nature of the presidential race, is already well-known to many voters.

"In many ways, it has reached a saturation point across the map," said one senior Democratic strategist, who requested anonymity to speak candidly about strategy. "It's a presidential campaign, people know who's running for president from which party."

For Strickland, however, Trump ads might soon become a regular feature.

Portman has successfully distanced himself from the New York mogul more than other GOP senators, overperforming him by better than 10 points in recent polls. That's making Democrats nervous that they are squandering a chance to capture a winnable seat.

As Election Day nears, and Senate Democrats increasingly try to capitalize on presidential nominee Hillary Clinton's lead in the polls, candidates like the former Ohio governor could more heavily press the connection between the Republican senator and Trump.

Democratic strategists caution that no decision about the broader use of TV ads featuring Trump has been made yet, but they acknowledge it's a possibility in the right race.

"You take it case by case," said the senior Democratic strategist. "There are some obvious places where it easily fits into a larger argument you're making about the Republican, or where it simply makes sense because of the demographics of a given state."

The strategist continued: "But there are also places where you might not need to bother. This entire race has been about nothing but Donald Trump since he announced last summer, and Republicans haven't been able to run away from him."